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is an aftermarket HEI (MSD) going to give me anything over a stock HEI?

Discussion in 'The Garage' started by Topdown, Sep 29, 2003.

  1. Topdown

    Topdown 1/2 ton status

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    I cant get a straight answer. Every person I talk to tells me something different and its pissing me off. I currently run an HEI distributor so 1/2 the people I talk to say no, there will be no benefit, the other half tell me I will "feel" the difference it makes.

    So...

    Will putting an MSD or even just a brand new HEI distributor in my truck benefit me with better mileage or more power?
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I upgraded to a complete MSD ignition and no difference felt. The MSD is definately better than the factory ignition. Roller bearing shaft in the distributor unlike the bushings that wear in the factory HEI. Unless you are having trouble with your current ignition I wouldn't recommend the upgrade if you are looking for more performance.
     
  3. 3car

    3car 1/2 ton status

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    4 wheeler,or 4 wheel and off road(cant remember)did a test a few years back with a chevy truck(70's model).stock hei,and several aftermarket units,msd,jacobs,accell,and a couple more.none provided much of a gain,i think all were less than 5 hp gain,some even lost power over stock!i think the stock hei is fine unless your turning alot of rpm's(4500+)for extended periods.upgrade your coil,and save the rest of your money.
     
  4. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    perfomance wise i do not think you will see much difference but with the msd you will have more options such as multiple spark,rev limiter, and other things.
     
  5. Hossbaby50

    Hossbaby50 3/4 ton status

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    Do you run a carb? If so you will probably feel a difference. I did. I actually notice a fair amount of difference when I swapped in the box (6 Offroad). I had installed other MSD components prior and post and got marginal differences. The coil did help a little, the wires helped a little, and the cap and rotor I didn't feel. The box I DID feel. I got everything that MSD claims when the box got installed.

    Better starting, better MPG, better power throughout the RPM band, and the best was throttle response. I noticed a huge difference there. I was sold on the MSD box for quite awhile.*

    * I am currently on my 2nd MSD coil and 2nd MSD box. Both I got replaced for free. I also think I might be having box troubles again but don't know that for sure yet. I am running the MSD 6 Offroad box and I think I picked the wrong box. I have heard that they overheat and die. My first box died at the beginning of the AZ summer last year and I think this one is dying at the end this year.**

    ** My best friend is running a MSD 6 (standard) on his 66 Chevy, and he said he noticed some of the same benefits I did after we installed it. He notice better MPG, less bog down (6cyl manual trans) on shifts, and better usable power. He has been running his box for over a year now, and his box I bought used threw CK5. His is holding up well.

    Harley
     
  6. TONYP

    TONYP 1/2 ton status

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    well...you can put a MDS sticker on the back of your truck /forums/images/graemlins/rotfl.gif

    as far as a stock HEI, you can get about 150,000 to 250,000 miles out of one...and if your not rev'ing that thing way up I think your fine... /forums/images/graemlins/thumb.gif
     
  7. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

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    MSD is the [darn] I love it more power better mileage easier starting REV LIMITER (if you get the box to go with the distributor well worth the money I'll never run a stock HEI again if I can help it /forums/images/graemlins/truck.gif
     
  8. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Are they better....probably
    Will you notice a difference in a stock motor....Yes if your original distributor is worn out, No if your distributor is in good shape.
    Proper maintenance of a stock distributor will do wonders at keeping performance up.
    If you have a modified motor with alot of compression or high revs, an aftermarket distributor or ignition system would help, but it doesn't sound like you need that.

    If it were me, I would pull the distributor, go to the local autoparts store and buy a new "pickup" assembly (located at the baseplate of the distributor), an MSD ignition module, adjustable vacuum advance, advance kit (with new weights and springs, but use the ones closest to stock), cap, rotor, and new high output coil. Once you have all the pieces, you can dis-assemble the distributor (hardest part is the roll-pin on the shaft holding the gear on). It may take a little persuasion to get the shaft out due to cooked on oil on the shaft. You can complete clean and rebuild it, plus it will give you an idea of how the ignition system works and should save cash over an aftermarket unit. You could also skip the hi-po stuff like MSD module and High output coil and save some more cash using stock replacements.

    If you have ???s on how to disassemble or reassemble, just PM me.
     
  9. diesel4me

    diesel4me 1 ton status Premium Member

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    If you go with the MSD distibutor,you will want to get the one for street use that has a vacuum advance--my friend bought the racing one with only centrifical advance for his 62 nova with a built 350--it has been giving him fits trying to adjust the spark curve with different bushings and springs,so he he will be re-installing his oem HEI or buying another MSD with the vacuum advance.It runs great if you hold it wide open,but on the street it needs the vacuum advance--it ran better with the oem unit! /forums/images/graemlins/blush.gif /forums/images/graemlins/thinking.gif
     
  10. ntsqd

    ntsqd 1/2 ton status

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    The stock HEI module loses dwell angle rather rapidly off-idle. Performance Distributors offers a module that didn't loose dwell angle in a test MISF & I did. We compared dwell b4 & after and the PD part still had 45* dwell at 4500 rpm (as high as we were willing to freewheel the engine).

    I converted one car from electronic ign to an MSD and it seemed like it cold started better with maybe a little better response. In testing to find an unknown problem I removed the MSD and can't say I noticed any loss.

    Like someone else already said, if your current dist is in good shape, it has the correct advance curve for the engine, the bushes aren't sloppy, the advance weights aren't frozen, and the advance weight pins aren't worn it probably won't make a lot of difference.
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    The only thing I really noticed is that mine idles better and that the rev limiter keeps me from blowing it up. Now I hold it to the floor with confidence.
     
  12. Thunder

    Thunder 3/4 ton status

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    Just get a DUI
    Performancedistributors.com
    Good stuff man. You will notice a nice diference. Maby pick up a mile or 2 per gal(depending on what shape the rest of the engine is in) And wont have to hassle with installing a box and all the extra wires n junk.
    Keep it simple. /forums/images/graemlins/thumb.gif
     
  13. leadfoot067

    leadfoot067 1/2 ton status

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    i run the pertronix hei kit in mine......better starting,no more pinging...pulls alot harder on the top end...where the stock hei runs out...ive also used just the accel hei coil...that made a difference just by itself....stock hei can most definetly be imoroved....
     
  14. Topdown

    Topdown 1/2 ton status

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    The engine is a mild build, he268 comp cam, Trick flow aluminum heads, peak (400+) hp @ 5500 rpm and peak torque (400+) at 4700rpm

    I dont crawl, I run sand and mud so I rev up to the 5000 - 5500 range.

    I currently run a stock cast manifold but will be swapping to a long-tube hedman header and a 2.25" exhaust (as soon as I get my muffs) so I am seriously looking to upgrade ignition to help that out. but this is a daily driver so I want reliable and good mileage.

    sounds like the MSD is a worthy upgrade... though the DUI looks VERY appealing... Oh, I have a shitload of low rpm ping right now... but I have no idea how to adjust the curve on a distributor...
     
  15. RustBuket

    RustBuket 1/2 ton status

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    [ QUOTE ]
    but I have no idea how to adjust the curve on a distributor...

    [/ QUOTE ]

    Different weights and springs will let your advance come in sooner or later.
     
  16. Topdown

    Topdown 1/2 ton status

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    That part I understand, but what I dont understand/know is how to tell how it should be advanced/weighted/sprung and how to change where it "comes in".

    I believe I need the advance to "come in" later in the RPM band, but I could have it all backward.

    I need a crash course on distributor curve adjustment.
     
  17. SUBFAN

    SUBFAN 1/2 ton status

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    Then compare with your current set up, and use heavier springs.

    Any race shops in your area? Having them recurve your distributor usually isn't to pricey.
     
  18. Don

    Don 1/2 ton status

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    I run MSD's module, cap, rotor, and coil. And I can say that is a major benefit to the stock HEI.

    The stock module will not saturate the coil as doe's the MSD. it is because of length of saturation to the coil which cause's the "hotter spark" GM's module was meant to do a stock vehicle, out of the factory into consumer's hand's.

    After i installed this there was a true 'by the seat of the pant's' improvement in acceleration, cold start up, hot start up, just overall a better setup. IMHO. /forums/images/graemlins/grin.gif
     
  19. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Your curve kit will come with full instructions on how to tune for the best performance. Of course you can't just think, oh, those springs look nice, I'll run those. You're not expected to be able too look at them and decide right away. They'll come with multiple sets of springs, all color coded, and an instruction book on how to use them.

    In short, you know just as much as I did the first time I messed with my distributor, and I'm very happy with how mine turned out. I used one light spring and one a little heavier and set my timing to 8* and have had good luck since.
     

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